During the granulation process of a feed pellet machine, there are individual feed pellets or individual feed pellets with different colors, commonly known as "flower feed". This situation is common in the production of aquatic feed, mainly manifested as the color of individual particles extruded from the ring die being darker or lighter than other normal particles, or the surface color of individual particles being inconsistent, thereby affecting the appearance quality of the entire batch of feed.
The main reasons for this phenomenon are as follows:
a) The composition of feed raw materials is too complex, with too many types of raw materials, uneven mixing, and inconsistent moisture content of the powder before processing feed particles.
b) The moisture content of the raw materials used for granulation is inconsistent. In the production process of aquatic food, it is often necessary to add a small amount of water to the mixer in order to compensate for the loss of water in the raw materials after ultrafine crushing. After mixing, it is then sent to the conditioner for tempering. Some feed manufacturers use an overly simple process to make feed - put the materials required for the formula directly into the mixer and add enough water, instead of carrying out a detailed and slow adding process according to professional requirements. Therefore, they find it difficult to ensure a balanced distribution of feed ingredients in terms of water solubility. When we use these mixed ingredients for conditioning treatment, we will find that due to the efficiency of the conditioner, the moisture content cannot be quickly dispersed evenly. Therefore, the maturity of the processed feed products under steam action varies greatly among different parts, and the color hierarchy after granulation becomes not clear enough.
c) There are recycled materials with repeated granulation in the granulation bin. The granular material after granulation can only be changed into the finished product after being cooled and screened. The screened fine powder or small particle material often enters the production process for re granulation, usually in a mixer or waiting for granulation silo. Due to the fact that this type of return material is re conditioned and granulated, if it is mixed unevenly with other auxiliary materials or mixed with return machine small particle materials after conditioning, it may sometimes produce "flower material" for certain feed formulas.
d) The smoothness of the inner wall of the ring die aperture is inconsistent. Due to inconsistent surface finish of the die hole, the resistance and extrusion pressure that the object experiences during extrusion are different, resulting in inconsistent color changes. In addition, some ring dies have burrs on the small hole walls, which can scratch the surface of the particles during extrusion, resulting in different surface colors for individual particles.
The improvement methods for the four reasons for producing "flower materials" listed above are already very clear, mainly controlling the mixing uniformity of each component in the formula and the mixing uniformity of the added water; Improving the quenching and tempering performance can reduce color changes; Control the return machine material. For formulas that are prone to producing "flower material", try not to directly granulate the return machine material. The return machine material should be mixed with the raw material and re crushed; Use high-quality ring dies to control the smoothness of the die holes, and if necessary, grind the ring die holes before use.
It is recommended to configure a two-layer dual axis differential conditioner and a two-layer extended jacket conditioner, with a quenching time of up to 60-120 seconds and a quenching temperature of over 100 ℃. The quenching is uniform and the performance is excellent. The use of multi-point air intake greatly increases the cross-sectional area of the material and steam, thereby improving the maturity of the material and improving the quenching and tempering effect; The digital instrument panel and temperature sensor can display the temperature of the conditioning, making it easy for users to control at any time.
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Post time: Jul-26-2023